Combined automatic and straight-air brake.



Patented Oct. 4, 1910.

2 r \Seru/ce [merqency WITNESSES INVENTOR 1n: Nos-ms PETERS cm, wnsumcmmD. c

WITH %TATE% PATENT FFIQ.

WALTER V. TURNER, OF EDGEl/VOOD, PENNSYLVANIA, ASSIGNOR TO THE WESTING-HOUSE AIR BRAKE COMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION OFPENNSYLVANIA.

COMBINED AUTOIVIATIC AND STRAIGHT-AIR BRAKE.

To all whom it may concern:

Be it known that I, WVALTER V. TURNER, a citizen of the United States,residing at Edgewood, in the county of Allegheny and State ofPennsylvania, have invented new and useful Improvements in CombinedAutomatic and Straight-Air Brakes, of which the following is aspecification.

This invention relates to fluid pressure brakes, and more particularlyto a combined automatic and independent brake apparatus in which asingle brake pipe is employed for controlling both the automatic andindependent applications of the brakes.

The principal object of my invention is to provide an improved apparatusof the above character of few parts and having considerable flexibilityin the matter of grading the brake cylinder pressure up or down.

In the accompanying drawing; Figure 1 is a central sectional view of thecontrolling valve mechanism; Fig. 2 a face view of the slide valvetherefor, showing the location of cavities and ports; Fig. 3 a plan viewof the valve seat for the above valve, showing the arrangement of theports therein; Fig. 4: a view in part section of the brake valveemployed; and Figs. 5 to 8 inclusive, diagrams illustrating the brakevalve in the respective positions of release, lap, service andemergency.

According to the preferred construction, illustrated in Fig. 1 of thedrawing, the controlling valve mechanism comprises a casing 1 having apiston chamber 2 containing piston 3, and a valve chamber 1, containinga slide valve 5.

The single combined automatic and independent brake pipe 9 is connectedto the piston chamber 2 at the outer face of the piston 3 and also leadsto a port 8 in the valve seat of the slide valve 5. The valve chamber 4is connected to a source of fluid pressure by way of a pipe 11 and apassage 10 in the valve casing. The source of pressure may be the mainreservoir on motor cars or an auxiliary reservoir on trailer cars, andthe passage 10 is provided with a reducing valve 12 to limit the degreeof pressure of the fluid which flows through the valve from the sourceof pressure, to a predetermined de- Specification of Letters Patent.

Application filed April 6, 1908.

Patented. Get. 4, 1910.

Serial No. 425.492.

gree according to the standard pressure carried in the brake system.

In its normal release position, the piston 8 occupies an intermediateposition, as shown in Fig. 1, and outward movement therefrom is resistedby a spring stop device 16. In this position a by pass 19 is open aroundthe piston to permit the flow of air from one side of the piston to theopposite side.

The preferred form of brake valve which I employ is illustrated in Fig.4 and comprises a casing 20 containing a rotary valve 21. The usual mainreservoir pipe 22 opens into the chamber above the rotary valve 21 andthe rotary valve is provided with a through port 23 for supplying airfrom said chamber to a port 24: which leads to the brake pipe 9. Therotary valve is also provided with a cavity 25 for connecting the brakepipe port 24 with an exhaust port 26 in the release position, and a portopening 27, connected by a passage in the rotary valve with a centralopening 28, which constantly registers with a central exhaust port 29.

In operation the parts are charged to a certain standard pressure asdesired, say 70 lbs. from the main reservoir on the motor cars, throughthe pipe 11 and passage 10, valve chamber i, and through the feed groove19 around the piston 3 to the chamber 2 and the brake pipe, the brakevalve being in lap position as shown in Fig. 6 during normal running. Itwill thus be seen that the system is charged through the controllingvalve mechanism from the source of pressure instead of the ordinarymanner through the brake valve.

On trailer cars, or cars not equipped with a source of fluid pressuresupply, the auxiliary reservoir may be charged from the brake pipe inthe usual manner, but I prefer to utilize an emergency valve 13, whichcontrols communication from the passage 14, leading to pipe 11 and thereservoir, and a chamber 17, which is connected by a passage 15 to thevalve chamber 4. The emergency valve being subject only to the pressureof a light spring. sufficient to normally hold the valve seated, it willbe seen that upon fluid under pressure being supplied to the brake pipefrom the motor car, air flows from the piston chamber 2 through the feedgroove 19 around the piston 3 to the valve chamber 1, and thence throughpassage 15 to chamber 17. The emergency valve 13 is lifted from its seatby the pressure in chamber 17, and air then flows through passage 14 andpipe 11 to the auxiliary reservoir, charging the same to the normalstandard pressure.

The parts being charged up to the standard pressure, if it is desired tomake an in dependent or straight air application of the brakes, thebrake valve is turned to service position, shown in Fig. 7, in which thethrough port 23 registers with brake pipe port 2st. The brake pipepressure is thereupon increased above the standard normal pressure acertain amount, say about five pounds, sufiicient to shift the piston 3to its inner position, the brake valve is then turned back to the lapposition, Fig. 6. The piston 3 is provided with seat rings or ribs 30adapted to make a tight joint in the inner position on a seating gasket31. The space intermediate said rings is in open communication with aport 32 leading to the slide valve seat, and the slide valve 5 isprovided with a cavity 33 adapted in the inner position to connect theport 32 with exhaust port 7 Thus the inner area of the piston 3, subject to the reservoir pressure in valve chamber 1, is considerablyreduced and consequently a low pressure 011 the brake pipe side of thepiston is suflicient to maintain said piston seated. Cavity 18 in slidevalve 5 also connects the brake cylinder port 6 with the brake pipe port8, so that the fluid under pressure in the brake pipe equalizes into thebrake cylinder. The pressure thus resulting in the brake cylinder willof course depend on the proportionate size of the brake cylinder, but Iprefer to employ a brake cylinder having such relation to the volume ofthe brake pipe that the equalized pressure will be about 10 pounds. Therelative areas of the piston 3, subject respectively to the brake pipepressure on one side and reservoir pressure on the opposite, are suchthat said piston is maintained seated even after the brake pipe pressureequalizes fully into the brake cylinder. The brake cylinder pressure maynow be readily increased as desired by again moving the brake valvehandle to the service position to admit fluid under pressure to thebrake pipe and thence through the cavity 18 to the brake cylinder. Inlike manner, the brake cylinder pressure may be graded down by turningthe brake valve from lap position to release position, shown in Fig. 5,in which the brake pipe port 24: is connected by cavity 25 in the rotaryvalve with the exhaust port 26. Upon the desired reduction in pressurethe brake Valve is returned to lap position. If it is desired toentirely release the brakes, the brake valve is held in the releaseposition.

I do not propose to permit the complete exhaustion of air from the brakecylinder and the brake pipe in the release position, for the reason thatthe emergency application is effected by such reduction in the brakepipe pressure, as will appear hereinafter, so that I interpose in theexhaust port 26 an excess pressure valve 341, which is adjusted toretain a pressure of about five pounds in the train pipe. As air isexhausted from the brake cylinder and the brake pipe a point is reached,somewhat less than the equalizing pressure of the brake pipe and thebrake cylinder, at which the reservoir pressure acting on the reducedarea of the inner side of piston 3 is suflicient to overcome the lowbrake pipe pressure on the outer face of the piston, so that said pistonis thereupon shifted outwardly. Upon leaving the gasket seat, the fullarea of the piston is exposed to reservoir pressure and consequently themovement of the piston is accelerated. On the piston attaining theintermediate position of release, the feed groove 19 is opened so thatthe fluid pressures on the opposite sides of the piston are permitted toequalize and at the same time the piston engages the spring stop 16. Theresistance of the spring stop and the rapid equalization of the opposingfluid pressures on the piston cause the same to stop in its releaseposition. The fluid under pressure which still remains in the brakecylinder is then released through the exhaust cavity 18 in the slidevalve 5 and exhaust port 7.

In order to steady and prevent too rapid movement of the piston 3 inshifting outwardly from the inner seat, I may also pro vide a pistonhead 35, connected to the piston 3 and closely fitting the bore of thevalve chamber 4, said piston being provided with a small port 36 topermit a gradual flow of air therethrough. Thus, as the piston 3 leavesits seat the pressure on the larger area thereof, which is now exposed,gradually rises to the reservoir pressure and so the tendency of thepiston to move out rapidly is lessened.

An automatic emergency application of the brakes occurs upon a completeemptying of the brake pipe, either by a break-in-two of the train orbursting of a flexible hose, or by turning the brake valve to theemergency position, as illustrated in Fig. 8, in which the large exhaustopening 27 is in full regis ter with the brake pipe port 24. The fluidunder pressure in the brake pipe is thus vented to the atmosphere andthe reservoir pressure acting on the inner face of piston 3 is thensufficient to overcome the tension of the spring 37 which acts on thespring stop 16, and the piston is shifted to its outer seat. The springstop 16 is so arranged that in its outward movement the emergency valve13 is engaged and thereby lifted from its seat, thus permitting fluid atthe full main reservoir pressure, or the auxiliary reservoir pressure onthe trailer car, to flow through passage 14 past the valve 13 to chamber17 and passage 15 and thence to the valve chamber 4:. In the outeremergency position of the piston, the slide valve 5 establishescommunication through a port 38 therein from the brake cylinder port 6to the valve chamber 1, so that the high reservoir pressure therein isadmitted to the brake cylinder, causing an emergency application of thebrakes. In order to prevent possible leakage of air around the stem ofthe spring stop 16 from chamber 17 to the brake pipe, a seating ring 39is provided on the piston 3, which is adapted to form a tight joint onthe usual emergency gasket. After an emergency application the brakesare released by increasing the brake pipe pressure, and this may be doneby turning the brake valve to the service position, Fig. 7, as will beapparent. Upon a suflicient increase in brake pipe pressure, with theassistance of the spring 37, the piston 3 is returned to releaseposition. In order to prevent leakage of air from the chamber 17 aroundthe stem of the spring stop to the piston chamber 2, which might occurwhen the brake pipe pressure is less than normal in making serviceapplications of the brake, I preferably provide a suitable seat 10 adjacent the stem and Within the chamber 17.

My invention has especial utility in connection with electric tractionservice, on account of its simplicity and by reason of the fact that theadvantages of the automatic brake and the flexibility and ease ofmanipulation of the straight air brake are secured with but one trainbrake pipe.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a fluid pressure brake, the combination with a brake pipe andbrake cylinder, of a valve mechanism operating upon a reduction in brakepipe pressure to supply air to the brake cylinder, and adapted uponincrease in train pipe pressure to move to a position for openingcommunication from the brake pipe to the brake cylinder, and means forholding the valve mechanism in said open position.

2. In a fluid pressure brake, the combination with a brake pipe andbrake cylinder, of a valve mechanism operating upon a reduction in brakepipe pressure to supply air to the brake cylinder, and operating upon anincrease in brake pipe pressure to establish a free open communicationfrom the brake pipe to the brake cylinder, and means for maintaining thevalve mechanism in the position for opening said communication tothereby permit the brake pipe pressure to equalize into the brakecylinder.

3. In a fluid pressure brake, the combination with a brake pipe, brakecylinder, and brake valve for controlling the brake pipe pressure, of avalve mechanism operating upon a reduction in brake pipe pressure tosupply air to the brake cylinder, and upon an increase in brake pipepressure to open communication from the brake pipe to the brakecylinder, and means for maintaining the valve mechanism in the positionfor opening said communication, to thereby permit the brake cylinderpressure to be increased or diminshed by manipulation of the brakevalve.

4;. In a fluid pressure brake, the combination with a brake pipe, brakecylinder, and brake valve for controlling the pressure in the trainpipe, of a valve mechanism operating upon a reduction in brake pipepressure to supply air to the brake cylinder, and upon an increase inbrake pipe pressure to establish a free open communication from thebrake pipe to the brake cylinder, and means for holding said valvemechanism in the position for establishing said free open communication,to thereby permit equalization of the brake pipe pressure into the brakecylinder and the increase or reduction of brake cylinder pressurethrough the brake pipe by manipulation of the brake valve.

5. In a fluid pressure brake, the combination with a brake pipe andbrake cylinder, of a valve and piston subject to the opposing pressuresof the brake pipe and a chamber and adapted upon a reduction in brakepipe pressure to supply air to the brake cylinder, and upon an increasein brake pipe pressure to open communication from the brake pipe to thebrake cylinder, and means for reducing the efiective area of said pistonsubject to the pressure in the chamber, in the position for openingcommunication from the brake pipe to the brake cylinder, to maintain thevalve and piston in said open position.

6. In a fluid pressure brake, the combination with a train brake pipe,of a valve device adapted to be shifted upon an increase in said brakepipe pressure to a position for supplying air from the brake pipe to thebrake cylinder and means for maintaining the valve device in saidposition.

7. In a fluid pressure brake, the combination with a train pipe andbrake cylinder, of an automatic valve device operating upon a reductionin train pipe pressure for supplying air to the brake cylinder and uponan increase in train pipe pressure for supplying air from the train pipeto the brake cylinder and means for holding said valve brake pipe andmeans for permitting equalidevice in the position for supplying air fromzation from the brake pipe into the brake the train pipe to the brakecylinder. cylinder.

8. In a fluid pressure brake, the combina- In testimony whereof I havehereunto set 5 tion with a. train brake pipe, of a valve demy hand.

vice operating upon an increase in pressure in the train brake pipe forsupplying fluid I from said train brake pipe to the brake cyl-Witnesses: inder, a brake valve for controlling the ad- R. F. EMERY, 10mission of fluid under pressure to said train WM. M. CODY.

WALTER V. TURNER.

